Is depression different from bipolar disorder?

Yes: Depression is a mood disorder that has dysmotivation, sadness, flat affect, disinterest in usually exciting activities (like sex, work, child rearing, volunteerism, housekeeping), irritability, sleep disruption, inability to perform tasks of daily activity, or interaction with friends or family. Bipolar disorder has these symptoms as well, but also has mood swings, extreme irritability, rages, .

Yes, technically but: Sometimes they are confused one with the other. When depression resists all antidepressant medication one has to think bipolar disorder, since in bipolar disorder individuals antidepressant meds often aggravate it. Major depression can evolve into bipolar disorder. Rarely bipolar can become major depression. Depression gets depression meds, bipolar - mood stabilizers & sometimes depression meds.